It is particularly important that donor and recipient be well matched for tooth transplantation because immunosuppressive drugs cannot be used to prolong their survival. At the present time it is not known to what degree humans be matched in order to assure the long-term survival of tooth allografts. The purpose of this research is to define the minimum criteria that must be met to insure a favorable outcome and to determine what immunological parameters should be monitored to detect in vivo sensitization after transplantation. For this purpose teeth will be transplanted among well matched strains of genetically-defined mice and between rhesus monkeys who have been typed for serologically-defined and lymphocyte-defined transplantation antigens. Post-transplantation analyses will permit correlations between in vitro immune assays and clinical evaluations to establish the probability of successful transplantation in humans.